Anchor lights - risks of not showing correct lights

[Ships_Cat]

I also have not had any problem seeing anchor lights at the masthead and wonder why others don't see them (and I don't think tht has anything to do with cats being able to see in the dark /forums/images/graemlins/smile.gif).

On the close in thing I go along with the concept that one should have seen it beforehand in any event, but I can still see them even when alongside from the loom (spelling?) on other masthead things such a windex, etc. In our own case we can clearly see the anchor light at the masthead is on just by looking up through a hatch from directly below (and I assume that others should be competent enuff to see it before they drive their boats into a similar perspective /forums/images/graemlins/smile.gif).

John

 

[BrendanS]

you don't have anywhere near the levels of light pollution in NZ that we do in parts of the UK and Europe

 

[Tisme]

Oh, I don't know /forums/images/graemlins/smile.gif

 

[Ships_Cat]

Not sure if it matters when one anchors in an area surrounded by city lights whether the city's population is 100,000 peeps ot 15 millions. Our situation may in fact be worse because we have lights on things called hills (classed as mountains over your way I think /forums/images/graemlins/smile.gif).

I got a big fright by not seeing the nav lights of a large sea going trawler while close coasting off the back drop of lights on the hills from a city of only around 60,000 (3 off us were on watch /forums/images/graemlins/frown.gif). Hardly London but we do have hellectricity out here /forums/images/graemlins/smile.gif so lights there were and fortunately he had seen us.

John

 

[BrendanS]

I meant light pollution rather than actual directly observable lights. It means lights in mast are less clearly visible. Bit like you can't see stars much around here, but go to west wales or scotland and you can see constellations that aren't visible in the south of uk

http://www.inquinamentoluminoso.it/download/mondo_ridotto0p25.gif

Taken image off and replaced by link as image was over large

 

[Ships_Cat]

Yer probably right, providing ones mast is at least a few hundred feet tall /forums/images/graemlins/smile.gif.

John

 

[BrendanS]

why? a mast doesn't have to be that high to be against the night sky

 

[Ships_Cat]

Just trying to get the light high enuff so's dim enuff to be affected. Talking about dim, do you really... er must go /forums/images/graemlins/smile.gif.

John

 

[BrendanS]

It's nothing to do with being dim, it's about contrast. If a light is presented against a sky which is white it's less easily seen than against a sky which is black. Light pollution around southern UK means that the sky at night is seldom black unlike in other parts of the world, hence masthead lights at more of a disadvantage.

Lights at deck level in moorings are often against an unlit coastline, so are more readily seen against a more dark background.

Varies betweens moorings though

 

[Ships_Cat]

No, referred to dim for exact reason you say - dim light has less contrast against a lit sky than a bright light /forums/images/graemlins/smile.gif.

John

 

[BrendanS]

ho hum. Bright light or dim light, neither will stand out as well in a sky full of light pollution as they would against a sky with much less light pollution

 

[Ships_Cat]

Lots of light pollution here right now cannot see any stars at all. Which reminds me perhaps you'd better get off to bed /forums/images/graemlins/smile.gif.

John

 

[BrendanS]

oh no, not letting up on this one /forums/images/graemlins/laugh.gif

As the map shows, you have very little light pollution in NZ, so a few miles down the coast from your medium sized cities you have very little light pollution of the skies. In the southern UK, light pollution is high, so even away from cities, the effect still has a major effect.

PS, found the image we discussed. pm me your email, I know I've got it but hidden in thousands of addresses in outlook

 

[Ships_Cat]

Was referring to the fact that it is daytime here at mo so very light polluted /forums/images/graemlins/smile.gif.

Have PM'd email address - many thanks for that Brendan..

Regards

John

 

[BrendanS]

well never can tell with antipodean forumites if they've actually taken on board the info or not

Email sent. Very limited selection. Will have to put them all up on a webpage for easier access. Most of them under 2 years old!

 

[MarkJohnson12345]

[ QUOTE ]
Then there are the LED things and they are very poor. Frankly, the LED and solar ones are not much better than nothing at all though give them their due...80% don't show anything!

[/ QUOTE ]


Not quite sure to what you refer to when you say "LED things" but there are special LED lights can be as bright at normal bulbs. I have tested them and they can be seen for over two miles, and have the advantage of using small amps, and lifetime is in 1000's of hours (20+).

 

[Anonymous]

The reason I said 'LED things' is because LEDs are almost invariably (though not always) packed in a housing that is a directional lens. Many LEDs are required together as an array to reach the required power and the result is usually a directional beam. For an anchor light you need an all-round beam so the arrangement needs to be more complicated - i.e. a 'thing' as opposed to just a bulb.

 

[MarkJohnson12345]

[ QUOTE ]
The reason I said 'LED things' is because LEDs are almost invariably (though not always) packed in a housing that is a directional lens. Many LEDs are required together as an array to reach the required power and the result is usually a directional beam. For an anchor light you need an all-round beam so the arrangement needs to be more complicated - i.e. a 'thing' as opposed to just a bulb.

[/ QUOTE ]


There are some very powerful LED's around with as you say a direction beam. Ours have a beam width of 40 degrees.

You are right in saying they come in arrays to cover the required vectors, and a lens is part of the light.

Anyway, the things as you say are good alternatives to conventional bulbs, though do cost more but with the adantages as said in previous mail

Regards

 

[Anonymous]

I don't know your company's products so can't comment in particular though in general LEDs will be the future (medium term, for a decade or two) I am sure, and there is no technical reason why an excellent LED anchor light could not be made at a price. But there are some lousy LED anchor lights hanging on peoples' boats. I say 'LED' - this is not based on inspection, but on the colour and low intensity.